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Chapter 10: Q. T10.1 (page 697)

A study of road rage asked separate random samples of 596men and 523 women

about their behavior while driving. Based on their answers, each respondent was

assigned a road rage score on a scale of 0 to 20. Are the conditions for performing a

two-sample t test satisfied?

a. Maybe; we have independent random samples, but we should look at the data to

check Normality.

b. No; road rage scores on a scale from 0 to 20 can’t be Normal.

c. No; we don’t know the population standard deviations.

d. Yes; the large sample sizes guarantee that the corresponding population

distributions will be Normal.

e. Yes; we have two independent random samples and large sample sizes.

Short Answer

Expert verified

The correct answer is:

e. Yes; we have two independent random samples and large sample sizes.

Step by step solution

01

Given information

We are given separate samples of 596men and 523women about their behavior while driving.

Conditions for performing a two-sample t-test: Random, Normal and Independent.

02

Explanation

Random: I'm satisfied because the samples were supplied to me at random.

Normal: Because each sample has a sample size of at least 30, it can be presumed to be satisfied.

Independent: Satisfied. Because the random samples were given to be separate, they are now independent. Furthermore, the sample sizes are less than 10%of the whole population.

Because all three conditions have been met, answer (e) is correct.

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Most popular questions from this chapter

TicksLyme disease is spread in the northeastern United States by infected ticks. The ticks are infected mainly by feeding on mice, so more mice result in more infected ticks. The mouse population, in turn, rises and falls with the abundance of acorns, their favored food. Experimenters studied two similar forest areas in a year when the acorn crop failed. To see if mice are more likely to breed when there are more acorns, the researchers added hundreds of thousands of acorns to one area to imitate an abundant acorn crop, while leaving the other area untouched. The next spring, 54of the 72mice trapped in the first area were in breeding condition, versus 10of the 17mice trapped in the second area.

a. State appropriate hypotheses for performing a significance test. Be sure to define the parameters of interest.

b. Check if the conditions for performing the test are met.

Friday the 13th Do people behave differently on Friday the13th? Researchers collected data on the number of shoppers at a random sample of 45grocery stores on Friday the 6thand Friday the 13thin the same month. Then they calculated the difference (subtracting in the order6thminus13th ) in the number of shoppers at each store on these 2days. The mean difference is -46.5and the standard deviation of the differences is 178.0.

a. If the result of this study is statistically significant, can you conclude that the difference in shopping behavior is due to the effect of Friday the 13thon people’s behavior? Why or why not?

b. Do these data provide convincing evidence at theα=0.05level that the number of shoppers at grocery stores on these 2days differs, on average?

c. Based on your conclusion in part (a), which type of error—a Type I error or a Type II error—could you have made? Explain your answer.

Bag lunch? Phoebe has a hunch that older students at her very large high

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There are two common methods for measuring the concentration of a pollutant in fish tissue. Do the two methods differ, on average? You apply both methods to each fish in a random sample of 18carp and use

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b. the one-sample z test for p.

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A random sample of size nwill be selected from a population, and the proportion of those in the sample who have a Facebook page will be calculated. How would the margin of error for a 95%confidence interval be affected if the sample size were increased from 50to 200?

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(d) It is divided by 2.

(e) It is divided by 4.
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